How to use submenu in rmarkdown navbar?

Question

I am trying to create a submenu in rmarkdown navbar

here is my _site.yml

name: Test dashboard
navbar:
  title: Test dashboard
  left:
  - text: by Commo (intake)
    menu:
    - text: "Menu"
      href: index.html
    - text: "SubMenu"
      menu:
      - text: "Item1"
      - href: index2.html 
      - text: "Item2"
      - href: index3.html 
output:
  html_document:
    include:
      after_body: footer.html
    css: styles.css
    source_code: embed
    lib_dir: site_libs
    mathjax: null
    self_contained: false
output_dir: _site

However for whatever reason the links of the submenu are not displayed properly. THey are below the section names, on a very thin line which has a few pixel height.

Does that make sense?

I am using

> packageVersion("rmarkdown")
[1] ‘2.1’

Answer 1

I believe I found why it didn't work correctly. When I remove extra dashes (-) before hrefs at submenu level everything seems to be ok.

Whole _site.yml looks like that:

name: Test dashboard
navbar:
  title: Test dashboard
  left:
  - text: by Commo (intake)
    menu:
    - text: "Menu"
      href: index.html
    - text: "SubMenu"
      menu:
      - text: "Item1"
        href: index2.html 
      - text: "Item2"
        href: https://getbootstrap.com/docs/4.4/components/alerts/
output:
  html_document:
    include:
      after_body: footer.html
    css: styles.css
    source_code: embed
    lib_dir: site_libs
    mathjax: null
    self_contained: false
output_dir: _site

I'm using the same rmarkdown version (2.1).